Measurement of in-shoe plantar triaxial stresses in high-heeled shoes

Foot problems such as pain and calluses are common for high-heeled shoe wearers. These problems may be related to the excessive local plantar loading, including pressure and shear stress. The shear stress is important on such a declined support surface of high-heeled shoe. The purpose of this study was to investigate the distribution of contact pressures and shear stresses simultaneously between plantar surface and high-heeled insole over specific regions utilizing in-shoe triaxial force transducers. The results showed that both the peak pressure and the peak shear stress occurred at the 2nd metatarsal head during walking and the average magnitudes of ten subjects were 386.9 kPa and 79.7 kPa respectively. The directions of anteroposterior and mediolateral shear stresses transferred from the posterior to anterior and from the lateral to medial respectively as the foot rolled forward from heel strike to toe off. The information on the distribution of plantar stresses may be useful for understanding of the foot biomechanics with high-heeled shoe and improvement of the high-heeled shoe design.